Variable voltage motor



1954' .1. L.. MOODY ETAL VARIABLE VOLTAGE MOTOR 3 Sheets-Sheet 1 FiledDec. 5, 1949 O O 2 0mm 0 v INVENTORS. .JOHN L... MOODY fi mHlm.

MORTON F. MHTTHEW Oct. 19, 1954 .1. L. MOODY ETAL 2,692,363

VARIABLE VOLTAGE MOTOR Filed Dec. 5, 1949 3 Sheets-Sheet 2 //0 -30.//0.2 4/2 Fa \r l' 25 4- 2.5 2

r 59 00 M r 0 LI 420 INVENTORS. JOHN L. MOODY BY NORTON E MRTTHEW 1954.1. I... MOODY ETAL VARIABLE VOLTAGE MOTOR 3 Sheets-Sheet 3 Filed Dec.5, 1949 W m m-H I I H w m m w m V m M m P L N N m u u mm V. B vn 0N6uunurn l .1 :IHI ILI. owns {IL mm mh Nb M3 m m%\ m \N\ 5 R n w% J IMF GmKN WW 3 mm mm Patented Oct. 19, 1954 UNITED STATES PATENT OFFICEVARIABLE 'VOLTAGE 'MOTOR John L. Moody, Oakland, and MortonPiMatthew,iBerkeley,-Calif., assignors to Friden Calculating Machine Co.,Inc., acorporation'ofv California {Application December 5, 194.9,(Serial No.131,088

4 Claims. -1

This invention relates to variable voltage motors for calculatingmachines and the like, and'more particularly to a method and means ofquickly and easily applying any one of a plurality of predetermined linevoltages to the field coils thereof.

It is an importantobject of the instant invention to provide a methodand means of alterably connecting the field coils in an electric motorinsuch a manner that any one of a plurality of predetermined line voltagesmay be applied thereto without removing any of the field coil turns fromthe circuit.

It is another object of the present invention to provide a method andmeans of quickly and easily changing the field coil connectionsinan-electric motor to conformto any one ofa plurality of predeterminedline voltage ranges, while at the same time maintaining all field coilsturns in the electrical circuit for all such ranges.

It is also an object of the invention to produce a highly compact andeasily adjusted switching arrangement for an electric motor havingsectionalized field coils on each pole piece thereof wherein all fieldcoil turns :are utilized Whenever voltages of high, low, andintermediate values corresponding to predetermined line voltage rangesare applied to the input-terminals of-the motor.

It is still another object of the present invention to produce a compactand linearly adjustable electrical switching arrangement which is ofsimplified design and :is selectively operable to connect thesectionalized field coil windings of an electric motor in series, inparallel, or in a predetermined series parallel relationship, dependingupon'which of a plurality of predetermined line voltages is to beapplied to the input terminals of the motor.

It is also an object of the present invention to produce an electricmotor having multiple-section field coils on each pole piece thereof andprovided with a compact and easily installed differentially positionableswitch adaptedto' be readily adjusted without the use of special toolsfor-alterably connecting the field coils of the motor in such a mannerthat any one of a plurality of predetermined line voltages may beapplied to the motor input terminals.

Further objects are to provide a construction of maximum simplicity,economy, and ease of assembly and disassembly, also such furtherobjects, advantages, and capabilities as willfully appear and as areinherently possessed by the-device and the invention described herein.

illustrated in the -ture 23 from rotating The invention further residesin-the combination, construction, and arrangement of parts accompanyingdrawings, and while there is shown therein a preferred embodimentthereof, it is to be understood that the same is illustrative of theinvention and'that the invention is capable of modification and changeand eomprehends other details of construction without departing from thespirit thereof, or the scope of the appended claims.

Referring to the drawings:

Fig. l is a side elevational view of an electric motor for driving acalculating machine or the like, showing a means for quickly and easilyaltering the field coil connections of the motor.

Fig. 2 is a schematic wiring diagram of the-arrangement illustrated inFig. 1.

Fig. 3 is similar to Fig. 2, but shows'three predetermined positions ofthe variable voltage adlusting device.

Referring now more particularly to the drawings in which like referencenumerals indicate like parts in the several views, there is showngenerally at 20 an electric motor for operating an automatic calculatoror similar business machine, which motor has a frame 2| removablysecured to a machine base 22. Motor 20 preferably is of a series typehaving stationary field coils and a rotating armature 23 adapted tointermittently or continuously drive the machine through the quickdisconnect self-aligning coupling 24, which armature preferably isprevented from rotating at speeds above a predetermined maximum by thespeed-limiting action of a centrifugal governor 25 which also rotateswith the armature shaft. Although a commutator-type series motor isoften preferable because such a motor can be conveniently operated oneither direct or alternating current and possesses high starting torqueand other desirable operating characteristics, in some business machineapplications it will be found that shunt-wound, compound-wound, or otherknown types of electric motors satisfactorily, in which case thecentrifugal governor25 may often be dispensed with.

Whenever the series-connected motor 2:) is used, however, a centrifugalgovernor 25 of conventional design effectively prevents the armaatabnormally high speeds under no load or light load conditions. Referringnow to Figs. 1, 2, and 3 it will be seen that the governor brushterminals 26 and 2T of centrifugal switch, or governor, 25 supplycurrent through suitableslip-rings tothe normally closed switch contacts28 and 29 mounted on the electrically non-conductive rotating disk 35.Although contacts 28 and 29 are normally held closed by the resilientpressure of their supporting leaf springs, this resilient pressure isovercome by centrifugal forces induced within governor whenever armature23 rotates at a speed higher than a pre etermined maximum, with theresult that contacts 28 and 29 move to their open position until suchtime as the speed of armature 23 falls below the critical value forwhich centrifugal switch 25 has been set. As is best shown in Fig. 3,current normally flows from conductor it, post 50, conductor Hi6, brush2'3, contacts 23 and 29, brush 26, and conductor l2! to motor brushholder 33, and thence to the motor, whenever switch 25 is closed. Whencontacts 28 and 29 are moved to their open position, however, currentflows through a shunt circuit beginning at post so, through resistor 3!,conductors l2t, EN. The resistor, as shown in Fig. l, is supported abovebase 22 by bracket 32. The resistor has a value adapted to reduce thevoltage applied by the motor brushes 33 and 34 to armature 23suiiieiently to cause the rotational speed thereof to fall below apredetermined value and allow the supporting springs to move contacts 23and 29 to their normally closed position. Condenser 35 is also connectedacross the terminals 90 and 91 in parallel with resistor 3!, whichcondenser has a capacitance adapted to minimize sparking between switchcontacts 28 and 29 during malteand-break movement thereof.

Each pole piece in the laminated frame 2i of the motor has wound thereona duplex field coil assembly, which dual field coil arrangement adaptedto produce field poles of opposite mag netization whenever current flowsthrough them. In a bipolar motor, for example, as shown in Fig. 3, theupper field coil assembly 32-3 is composed oi a first section 38 havingterminals 39 and it, and a second section 4! having terminals :2 and 33.Both upper coil sections 33 and 4H have substantially an equal number ofturns thereon, the number of turns in the sections preferably beingselected in such a manner to eniciently operate the motor at its lowestoperatingline voltage when connected electrically in parallel, and bothcoil sections are wound on the associated pole piece in the samedirection so that the individual coil sections have a cumulativemagnetic eilect on the pole piece. In like manner, the lower field coilassembly 3? is composed of a first coil section alt having terminals and45, and a second coil section ll which is provided with terminals Q3 andE9.

Differentially positionable means is also provided for easily, quickly,and alter-ably connecting the individual coil sections which comprisethe respective upper and lower field coil assemblies 36 and 3 in such amanner that any one of a plurality of predetermined line voltages may beapplied to the motor. An insulated terminal block (Fig. 1) havingmetallic male power input connectors 5t and 5? extending therethrough issuitably secured to base 22. Block 55 has a right angle bracketextension 58 extending upwardly therefrom so as to form a suitableinsulated support for the vertically disposed and easily installedvariable voltage adjusting switch 59. Voltage adjusting switch 59 is ofa simplified laterally slidable and compact construction, includes arelatively fiat fixed vertical support i i composed of Micarta, hardrubber, or similar nonconducting material having a longitudinallydisposed rectangular slot or groove therein adapted III to receive andsupport a coacting slide 8| of sim iiar nonconducting material for freesliding lateral movement along the coaoting ways 58 of the fixed support56. Slide ti carries a pair of laterally spaced metallic contactors 52and 63 longitudinally disposed along the upper edge thereof, and haslongitudinally disposed along its lower edge, a similarly spaced pair ofelectrically conductive connectors e4, $5 which are longitudinallymovable with slide El. Slide all also has disposed longitudinallytherealong in a position between the upper and lower movable connectorsthereof a plurality of equidistantly-spaced holes "59a, lilb, and His,each-of which is adapted to register with a single hole in fixed support59, which hole is tapped to receive a locking screw 69 adapted toadjustably secure slide on in one of a plurality of predeterminedpositions relative to th support Bil. The "most end of slide 5i is alsoprovided with dicator plate 56 having a plurality of predeterminedoperating voltage ranges stamped or printed thereon, which ranges arelaterally spaced along slide 6! to correspond with the lateral spacingof the holes lea, 10b, and 180. Plate 58 is suitably divided intosections in such a ner that only one section at a time can be viewedthrough the window or aperture 8'5 in the cover plate or housing ii ofthe machine. Thus, when indicator section lite, labeled with apredetermined lower operating voltage range such as 11L- to volts,appears through window as shown in Fig. l, the lateral displacement .de55 along support fit determined by the hole "lea. Similarly, theappearance of indicator section 652) bearing the intermediate voltagerange 150 to volts through aperture 6? is determined by hole 'fllb inslide 5!, and the appearance through window 5? of the high voltagesection labeled 190 to 236 volts, indicates that switch 59 is in itshighest voltage adjusting position, wherein slide 6i is secured tosupport 6 3 by inserting screw through hole lilo.

Laterally spaced apart at predetermined intervals along the upper edgeof switch support 6t, and secured thereto by rivets or other suitableattaching means, is a plurality of stationary leaf spring contacts l2, Hand i5 composed of Phosphor bronze or similar electrically conductivematerial, each such contact having an inwardly extending free endadapted to extend over and be resiliently held against one of the uppermovable connectors so as to form a wiping contact and good electricalconnection therewith. The lateral spacing between contacts l2, l3 andbetween contacts id, 35 is slightly less than the length of therespective connectors 52 and 53, but the spacing between contacts i3, i5is substantially less than the length of these connectors. Contact 12 isconnected to brush terminal 2? by conductor me, post Gil, and conductor36 and also to terminal 39 of upper field winding 33 by conductor NH.The other terminal 48 or" upper field winding 36 is connected to contactby conductor 582. Upper field winding ll has one end 32 connected tocontact '53 by conductor Hi3 and has its other terminal d3 connected tocontact 15 by conductor tilt. vContact 75 is also connected, by means ofconductor Hi5, to line terminal 56 on block 55 through a micro-switch 86having normally open contacts 85 and 82 (shown in Fig. 5) adapted to beclosed by suitable means associated with the switch actuator arm 83.

A plurality of similarly inwardly extending stationary leaf springcontacts 75, ll, l8, and F9 are also affixed to the lower edge of switchsupport 5t iinafsuch ca manner as to form ;a :wiping :electricalconnection with the lower movable: connectors :64 and w 65 :carried :byslide 6 I. The lateral spacing betweendnterior :contacts Ti, 'I'l8 :isslightlydess than :the length .of connectors .64 ilateral'spacingbetween .contacts :16, 11 andrbetween-contacts 18, Wis substantiallyless than the spacing-between the interior contacts 11,18. 'Con- :tact:18 is connected to one terminal :45: of lower field .coil Mby-conductor H9, the other terminal 46 of which isconnected'to contact:18 by conductor IH. Lower field coil ll'has one terminal 48connectedto'contact 'l'l'by conductor H2 and dts-other terminal--49connected -,to contact lilby conductor 1 [-3, the latter being alsoconnecte'd'to xline terminal $51 on terminal block 55 by .con-

ductoritM.

Operation *Wheneverit-is desired tooperate motor z from a low voltagesupply, such as a voltage falling in the range 1'10-to 150 volts,screw-Silis removed and slide 6| is shifted laterally along support 66.tothea' position (shown in Figs..1 and 2, and in .ifull lines in Fig.3) whereinsection 66a on'the indicator plate is visible through viewingaper- Lturefi'l in cover plate "1|. Screw 69 is then'in Iserted throughhole "a- "soas 'to secure slide 6| 'iinzthis'adj ustedposition withrespect to the switch :support 60. Figs. 1 "and 2, as well as the solid"line positions"Ot'theicontacts"62, 63, 64 and I65 'inFig. 3,illustrates this :a "position or low voltage adjusted positionof slide6! wherein both section '38 and "of upper coil assembly 36 areelectrically connected 'in 'parallel, and wherein pboth sections rid-and'4Tof lower coil assembly 31 are similarly connected electrically inparallel.

In order to'operate motor '28 from a power supply .whose potential fallswithin a predetermined high voltage range, such as a range 190 to230volts, preferably having a magnitude of about twice that of the lowvoltage range, it is only necessary to remove screw 69 and laterallydisplace slide 6| outwardly towards the right to the 0 position so thatthe movable connectors carried by slide 6! assume the outermost dottedline positions 620, 63c, 64c and 650 illustrated in Fig. 3, whereinportion 660 of the indicator plate appears through the viewing aperture61. Slide BI is then secured to support 60 in its newly adjusted 0position by inserting screw 69 through hole 180, and it will be apparentfrom Fig. 3 that the upper connectors 62, 63 move with slide 6! to thepositions 820 and 630 wherein both upper field coil components 38 and 4|are electrically connected in series. Similarly, the lower connectors64, 65 move to the positions 64c and 650 wherein they operate to connectboth lower field coil components 44 and 41 electrically in series.

A third predetermined or I) adjusted position of slide 6| is alsoprovided intermediate the low voltage position illustrated in Fig. 1 andthe high voltage position shown in Fig. 3. This intermediate b positionis obtained by moving slide 6| so that section 66b of the indicatorplate, labeled 150 to 190 volts, appears through window 67. Slide BI isthen secured in the b position by inserting screw 69 through hole 78b,and in this intermediate position the upper connectors 62, 63 move tothe dotted line positions 62b, 631) shown in Fig. 3 so as to connect theupper field coil components 38 and 4| electrically in series, while thelower connector 64, 65 carried by slide 6| are simultaneously moved tothe positions 641),

and 65,; but the 3' 28512, where sthey :operate to field coil elements4.4 and .47 1 electrically iniparallel.

readily installed, and :switching :arrangement along and in such channeland to be thereinby the inward overhang of :tacts, releasable holdingmeans'extending through :said ;slide "in adjusted position,

.Thus, :it will be :seen that --a .highly compact, .easily adjusted:circuit is produced wherein :a parallel circuit connection is :provided"within field "coil assemblies 35,13! :duringlowvoltage :op- ;eration,i-and ra. series circuit connection .is pro- "vided .internally .therein"during .high voltage operation. .For intermediate voltages, f thevariable voltage "adjusting device isflalso :easily :moved to anintermediate :adjusted position "wherein half .ofith-ezfieldnoilassemblies-.havetheir sectionalized iwindings :electrically connected inseries while the remainingifield :coil; assembliesi have all fsec--tionalizedwwindings electrically :connectedingpar- 531181.

'Weclaim: .1. Aseries wound bipolar z'electricirrntor having amulticoiltfield:winding, 'each of the coils -of:said winding havingtwoseparate terminals; and switchmeansfor variously'connecting suchcoilswith respect to each other to adapt said .motor iorusewithdiffering voltagesources-of power, said switchmeans including: arectangular sheet of .insulation, opposed raised edge insulationportions'secured to said sheet and form-- ing therewith a channel,spring clip-contacts .along and :secured .to 'asaid portion andoverhangingztheedges of said portion, the spring-clip rcontacts being intwo .diiferently spaced group arrangements, in and extending across suchchannel an insulating slide adapted to :move freely retained saidclipcon-- said slidezand-into said rectangular sheet to hold andconductor bars ;on.:a-nd secured to ithe face oi-said slide adjacentsaid clip-contacts for bridging between various of said clip-contacts toeffect Various connections between said coils as said slide is movedalong such channel; and each said terminal of three of said coilssecured to a separate one of said clip-contacts, whereby, the fields ofsaid three coils will always be cumulative when said motor is operated,and: for a high voltage source, said three coils will be nonparallelwith other coils and will be in series with each other; for anintermediate voltage source, two of said three coils will be connectedin parallel with each other and in series with the third coil which willbe nonparallel with other coils; and for a low voltage source of power,said three coils will be conne zited so that each is in parallel withanother 001.

2. A series wound bipolar electric motor havmg two coils on each of saidpoles to form a field winding, each of the coils of said winding havingtwo separate terminals; and switch means be retained therein by theinward overhang of said clip-contacts, releasable holding means ex-;connect ithe lower tending through said slide and said rectangularsheet and operating to hold said slide in a selected adjusted position,and conductor bars on and secured to the face of said slide adjacentsaid clipcontacts for bridging between various of said clipcontacts toefiect various connections between said coils as said slide is movedalong such channel; and each said terminal of said four coils of saidfield winding secured to a separate one of said clip-contacts, whereby,the fields of said coils will alway be cumulative when said motor isoperated, and: for a high voltage source of power, said coils arenonparallel and are in series with each other; for an intermediatevoltage source, two of said four coils are connected in parallel witheach other and in series with the other two nonparallel coils; and for alow voltage source of power, said four coils are connected so that twoof said coils are in parallel with each other and in series with theother two which are connected in parallel with each other.

3. A motor drive system comprising in combination, an apertured casing,a motor supported in said apertured casing, a plurality of fieldwindings in said motona switch supported in said casing and operable toselectively change the circuit conditions of the field windings relativeone to another, a fixed contact supporting member in said switch, amovable contact supporting member operable for movement relative to saidfixed contact supporting member, releasable holding means to adjustablyhold said movable contact supporting member in adjusted positionrelative to said fixed contact supporting member, and indicia on saidmovable contact supporting member to indicate the voltage range of theinstant arrangement of the field coils, said indicia being visiblethrough an aperture in said casing.

4. In a calculating machine, a variable voltage motor drive systemcomprising, in combination,

an apertured casing, a motor supported in said casing, a plurality offield windings in said motor, a switch supported in said casing andoperable to be set to selectively connect said field windings inpredetermined arrangements to condition said motor for operation atpredetermined voltage ranges, a movable member in said switch, saidmovable member carrying contacts and being movable relative to a fixedmember supporting contacts, holding means engageable with said movableand fixed members and operable to hold said movable and fixed members inrequired relative positions, and groups of indicia on said movablemember to indicate the voltage range in which the motor is renderedoperable by the instant setting of said switch, said indicia beingobservable through an aperture in said casing.

References Cited in the file of this patent U'NITED STATES PATENTSNumber Name Date 271,175 Wheeler et al Jan. 23, 1883 390,906 Ries Oct.9, 1888 433,360 McLaughlin July 29, 1890 638,522 Rae Dec. 5, 1899765,209 Storer July 19, 1904 1,089,564 l-lull Mar. 10, 1914 1,608,613Oswald Nov. 30, 1926 1,895,096 Doloukhanofi J an. 24, 1933 2,064,828Grohsgal Dec. 22, 1966 2,077,904 Shepard Apr. 20, 1937 2,238,696 HanleyApr. 15, 1941 2,466,900 Knopp Apr. 12, 1949 FOREIGN PATENTS NumberCountry Date 569,638 Germany Feb. 10, 1933

